We, who think like animals living in small groups, must structure a global world. We believe in universal human rights and believe racism and war are wrong. On the other hand, it is our nature to be cooperative and loving almost exclusively with the members of the group to which we feel we belong.

You should know as much as you can about the human species if you have a hand in designing human society. Of course, I'm not saying that you can derive moral rules from nature - that's deriving an ought from an is, as the philosophers say - but you do need to know what kind of animals we are if you want to design a stable society.

As in a Russian doll, however, the outer layers always contain an inner core. Instead of evolution having replaced simpler forms of empathy with more advanced ones, the latter are merely elaborations on the former and remain dependent on them. This also means that empathy comes naturally to us. It is not something we only learn later in life, or that is culturally constructed.

Male chimpanzees have an extraordinarily strong drive for dominance. They're constantly jockeying for position.

Male bonobos really don't fit the human male ideal.

Morality, after all, has nothing to do with selflessness. On the contrary, self-interest is precisely the basis of the categorical imperative.

It is not only visitors to the zoo who are fascinated but uneasy in the presence of chimpanzees; the same is true of scientists. The more they learn about these great apes, the deeper our identity crisis seems to become. The resemblance between humans and chimpanzees is not only external. If we look straight and deep into a chimpanzee’s eyes, an intelligent, self-assured personality looks back at us. If they are animals, what must we be?